You need to change the editing mode from DV Playback to Video for Windows. Do this by choosing new project and clicking the "Custom Settings" tab then change it under the General heading. Then you can change the compressor.

Yep, tried this, and I can indeed access the different video codecs then--but under New Project Settings/CAPTURE, there's a message next to the Video for Windows input string that says: "Unable to access capture driver."

When I choose Capture/Movie, my virtual screen is grey, and, though the virtual deck works and activates the input camera, nothing happens when I try to capture.

I don't have a video camera at the moment so I can't check this out, but I don't think you can capture straight from a miniDV camera as a Huffy avi. You probably have to capture to the usual Microsoft DV codec and then render out of Premiere as a Huffy compressed avi.